This invention relates generally to method and apparatus for manipulating the spine and more particularly to method and apparatus for restoring curvature to a human spine.
The human spine is a column comprising thirty-three small bones or vertebrae for supporting the body. Two additional vertebrae atop the spine, the atlas and the axis, support the skull and allow it to rotate on the spine. Immediately beneath the axis are seven cervical vertebrae that make up the neck. The twelve bones immediately below them are the thoracic vertebrae of the back. These are followed by five bones that comprise the lumbar vertebrae in the small of the back. At the bottom of the spine, five bones, separate at birth, are fused during aging to form the sacrum between the hip bones. Beneath the sacrum is the coccyx, or tailbone, a single bone composed of four fused vertebrae.
The cervical and lumbar vertebrae form concave curves that alternate with a convex curve of the thoracic vertebrae to support the body and absorb shock. The resulting shape of the spine crosses the body's vertical center of gravity, weaving back and forth. The cervical curve allows the body to hold the head up without undue strain. The lumbar curve provides balance to the body and is essential for walking erect. These curves thus provide much greater stability and strength to the body than a comparable straight column could.
Loss of the spinal curves can be crippling for the body in general and the back in particular. This can occur through aging, injury, or simply poor posture. To compensate, the body responds with muscular action in an attempt to hold the head and body erect. But these muscles eventually strain, further damaging the body's health.
Recognizing this, varying methods and apparatus have been used in an attempt to manipulate the spine. U.S. Pat. No. 2,461,102 to Ackerman, for example, discloses a posture correcting apparatus employing spaced-apart rollers for rolling longitudinally along both sides of the spine. One set of rollers is mounted within a table on which the body lies, with the second set moving longitudinally along the table on top of the body.
Stretching the spine is another method employed to manipulate it. U.S. Pat. No. 2,660,999 to Thornton discloses a spinal alignment device comprising a table and a pair of opposed harnesses. One harness at the top of the table mounts to the head, and the second harness at the foot of the table mounts to the hips. The harnesses then pull in opposite directions away from each other to strengthen the spine.
A third method applies force directly to the spinal curvatures. U.S. Pat. No. 3,640,272 to Hussey illustrates this approach. A therapy table includes a cervical support shape to rest within the cervical concavity of the spine, with the body resting supinely upon the table. The body is then placed under longitudinal traction at the head and feet to align the spine.
The use of spinal supports is also employed in U.S. Pat. No. 3,550,587 to Kawada. Kawada discloses a device shaped to fit within the lumbar concavity in conjunction with a support fitting within the cervical curve of the spine. Pressure is applied to the spine solely by the weight of the body. The device then vibrates to massage the lower back.
Although these methods and associate apparatus may alleviate spinal discomfort, none has proven very effective in restoring lost spinal curvature. They and other devices in the prior art rely solely on the weight of the body as a active force. Without the exertion of muscular action to assist in holding the spine correctly, the body does not develop a "memory" of the correct spinal curvature and soon reverts to its former poor condition.